It has been observed that 48 percent ACS reagent grade hydrofluoric acid reacts very vigorously with lunar or geological samples. Standard textbooks recommend the use of 0.5 to 0.8 gram of samples for treatment with hydrofluoric acid. [Textbook of Quantitative Inorganic Analysis, I. M. Kolthoff and E. B. Sandell, 3d Ed., Macmillan Co., New York (1952), page 711; Elements of Quantitative Analysis, Theory and Practice, H. H. Willard, N. H. Furman and C. E. Bricker, 4th Ed., D. Van Nostrand Co., Inc., New York (1956), page 397]. It has also been observed that with the recommended relatively large amount of sample the reaction with hydrofluoric acid is so vigorous as to cause loss of sample due to bumping and spattering. Standard textbooks (ibid, Kolthoff et al, page 711; Willard et al, page 298) recommend the sequential addition of water, sulfuric acid and hydrofluoric acid for the dissolution of mineral samples. It has been found, however, that the recommended order of addition materially diminishes the vigor or reactivity of hydrofluoric acid so that long periods of time, e.g., six or more hours, are necessary to completely dissolve a sample.
If accurate results are to be obtained in quantitative analyses, it is imperative that the samples to be analyzed be completely dissolved. If the solution contains undissolved or precipitated sample, the analytic results will be inaccurate. The results will also be inaccurate if sample is lost during the dissolution procedure. It is also important to complete the dissolution in as short a time as possible.
It is an object of this invention, therefore, to provide a method for completely dissolving "hard to dissolve" samples rapidly and efficiently for subsequent analytical determinations.
Another object of the invention is to provide a method for the complete dissolution of lunar and geological samples for subsequent accurate chemical analysis.
Other objects and advantages of the invention will become apparent to those skilled in the art upon consideration of the accompanying disclosure.